| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for producing (meth)acrylic acid, which is capable of easily preventing polymerization of (meth)acrylic acid, when purified (meth)acrylic acid is obtained from crude (meth)acrylic acid by repeatedly performing a crystallization operation a plurality of times.SOLUTION: The process for producing (meth)acrylic acid comprises producing purified (meth)acrylic acid from crude (meth)acrylic acid by repeating a crystallization operation "n" times to obtain a (meth)acrylic acid melt from a (meth)acrylic acid-containing solution. In the process, a polymerization inhibitor is not added to a (meth)acrylic acid melt obtained in the melting step in each of the first to n-1 th crystallization operations and to a (meth)acrylic acid-containing solution subjected to the crystallizing step in each of the second to nth crystallization operations; and the concentration of the polymerization inhibitor in a (meth)acrylic acid-containing solution subjected to the crystallizing step of the first crystallization operation is adjusted so that the concentration of the polymerization inhibitor in a (meth)acrylic acid-containing solution subjected to the crystallizing step of the nth crystallization operation is 2 ppm by mass or higher. |
